TWI833842B - Ion exchangeable, opaque gahnite-spinel glass ceramics with high hardness and modulus - Google Patents

Abstract

An opaque gahnite-spinel glass ceramic is provided. The glass ceramic includes a first crystal phase including (Mg _x Zn _1-x )Al₂ O₄ wherex is less than 1 and a second crystal phase includes at least one of tetragonal ZrO₂ , MgTa₂ O₆ , mullite, and cordierite. The glass ceramic has a Young’s modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

Description

Ion-exchangeable opaque zinc spinel-spinel glass ceramic with high hardness and modulus

This application claims the benefit of priority to U.S. Provisional Application No. 62/773,682, filed November 30, 2018, the contents of which are based on and incorporated by reference in their entirety.

This specification generally relates to opaque glass-ceramic compositions. More specifically, this specification is directed to opaque zinc spinel-spinel glass ceramics that can be formed into housings for electronic devices.

Portable electronic devices such as smartphones, tablets, and wearable devices such as watches and fitness trackers continue to become smaller and more complex. As such, the materials conventionally used on at least one exterior surface of such portable electronic devices continue to become more complex. For example, as portable electronic devices become smaller and thinner to meet consumer demands, the casings used in these portable electronic devices also become smaller and thinner, thereby increasing the demand for components used to form these devices. Materials have put forward higher performance requirements.

Therefore, there is a need for materials with higher performance properties such as damage resistance for use in portable electronic devices.

According to aspect (1), a glass ceramic is provided. The glass ceramic includes: a first crystal phase including (Mg _x Zn _1-x )Al ₂ O ₄ with x less than 1; and a second crystal phase including tetragonal ZrO ₂ and MgTa ₂ O _6. At least one of mullite and cordierite; wherein the glass ceramic is opaque in the visible light range, the Young's modulus is greater than or equal to 90 GPa, and the hardness is greater than or equal to 7.5 GPa.

According to aspect (2), the glass ceramic of aspect (1) is provided, further comprising at least one of Li ₂ O and Na ₂ O.

According to aspect (3), the glass ceramic of aspect (1) is provided, further including Li ₂ O and Na ₂ O.

According to aspect (4), there is provided a glass ceramic according to any one of aspects (1) to (3), wherein x is greater than 0.

According to aspect (5), there is provided the glass ceramic of any one of aspects (1) to (4), further comprising greater than or equal to 35 mol% to less than or equal to 60 mol% SiO ₂ .

According to aspect (6), the glass ceramic of any one of aspects (1) to (5) is provided, further comprising: 35 mol% to 55 mol% SiO ₂ ; greater than or equal to 18 mol% Al ₂ O ₃ ; Greater than or equal to 5 mol% MgO; and greater than or equal to 2 mol% P ₂ O ₅ .

According to aspect (7), the glass ceramic of any one of aspects (1) to (6) is provided, further comprising: 0 mol% to 14 mol% ZnO; 0 mol% to 5 mol% TiO ₂ ; 0 mol 0 mol% to 5 mol% Na ₂ O; 0 mol% to 5 mol% Li ₂ O; 0 mol% to 2 mol% BaO; 0 mol% to 4 mol% B ₂ O ₃ ; 0 mol% to 1 mol% CaO; 0 mol% to 3 mol% Eu ₂ O ₃ ; 0 mol% to 6 mol% Ta ₂ O ₅ ; 0 mol% to 5 mol% La ₂ O ₃ ; 0 mol% to 0.1 mol % As ₂ O ₅ ; and 0 mol% to 0.3 mol% SnO ₂ .

According to aspect (8), there is provided a glass ceramic according to any one of aspects (1) to (7), wherein ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃ ≤ 6 mol%.

According to aspect (9), there is provided a glass ceramic according to any one of aspects (1) to (8), wherein the glass ceramic does not substantially contain TiO ₂ .

According to aspect (10), a glass ceramic according to any one of aspects (1) to (9) is provided, wherein ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃ ≤ 5.5 mol%, And the glass ceramic includes at least one of the following: La ₂ O ₃ ; Ta ₂ O ₅ ; and greater than or equal to 2 mol% Li ₂ O.

According to aspect (11), a glass ceramic according to any one of aspects (1) to (9) is provided, wherein ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃ ≤ 5.1 mol%, And the glass ceramic includes less than 2 mol% Li ₂ O and does not substantially contain La ₂ O ₃ and Ta ₂ O ₅ .

According to aspect (12), there is provided a glass ceramic according to any one of aspects (1) to (11), wherein the crystallinity of the glass ceramic is at least 35 wt%.

According to aspect (13), there is provided the glass ceramic of any one of aspects (1) to (12), wherein the crystallinity of the glass ceramic is greater than or equal to 35 wt% to less than or equal to 60 wt%.

According to aspect (14), there is provided the glass ceramic of any one of aspects (1) to (13), wherein the Young's modulus of the glass ceramic is greater than or equal to 100 GPa and less than or equal to 125 GPa.

According to aspect (15), there is provided the glass ceramic of any one of aspects (1) to (14), wherein the hardness of the glass ceramic is greater than or equal to 8 GPa and less than or equal to 13 GPa.

According to aspect (16), there is provided a glass ceramic according to any one of aspects (1) to (15), wherein the glass ceramic is substantially colorless.

According to aspect (17), there is provided the glass ceramic of any one of aspects (1) to (16), wherein the second crystal phase includes tetragonal ZrO ₂ .

According to aspect (18), there is provided the glass ceramic of any one of aspects (1) to (16), wherein the glass ceramic does not substantially contain ZrO ₂ and the second crystal phase includes MgTa ₂ O ₆ .

According to aspect (19), there is provided a glass ceramic according to any one of aspects (1) to (16), wherein the glass ceramic substantially does not contain a nucleating agent, and the second crystal phase includes mullite and cordierite.

According to aspect (20), there is provided the glass ceramic of any one of aspects (1) to (19), further comprising a compressive stress region extending from the surface of the glass ceramic to a compression depth.

According to aspect (21), a consumer electronic product is provided. A consumer electronic product includes: a housing, including a front surface, a rear surface and sides; and electronic components at least partially within the housing, the electronic components at least including a controller, memory and a display, the display being located on or adjacent to the housing a money surface; and a covering substrate arranged above the display, wherein at least a portion of the housing includes the glass ceramic of any one of aspects (1) to (19).

According to aspect (22), a consumer electronic product is provided. A consumer electronic product includes: a housing, including a front surface, a rear surface and sides; and electronic components at least partially within the housing, the electronic components at least including a controller, memory and a display, the display being located on or adjacent to the housing money surface; and a covering substrate arranged above the display, wherein at least a portion of the housing includes the glass ceramic of aspect (20).

According to aspect (23), a method is provided. The method includes: ceramizing a precursor glass to form a glass ceramic that is opaque in the visible range, wherein the glass ceramic includes: a first crystalline phase including (Mg _x Zn _1-x )Al ₂ O ₄ , where x is less than 1; and The second crystal phase includes at least one of tetragonal ZrO ₂ , MgTa ₂ O ₆ , mullite and cordierite; the Young's modulus of the glass ceramic is greater than or equal to 90 GPa, and the hardness is greater than or equal to 7.5 GPa.

According to aspect (24), there is provided the method of aspect (23), further comprising forming nuclei in the precursor glass prior to ceramizing.

According to aspect (25), there is provided the method of aspect (24), wherein forming the nucleation includes heat treating the precursor glass at a temperature of at least 700°C for a period of at least 1 hour.

According to aspect (26), there is provided a method of any of aspects (23) to (25), wherein ceramizing includes heat treating the precursor glass at a temperature of at least 750°C for a period of at least 30 minutes.

According to aspect (27), there is provided a method of aspect (23), wherein the method does not include a separate nucleation step.

According to aspect (28), there is provided the method of aspect (23), wherein ceramizing includes irradiating a precursor glass with a laser to form a glass ceramic.

According to aspect (29), there is provided a method of any one of aspects (23) to (28), further comprising an ion exchange glass ceramic.

According to aspect (30), there is provided the method of aspect (29), wherein the ion exchange includes contacting the glass ceramic with a mixed ion exchange bath.

According to aspect (31), glass is provided. Glass includes: 35 mol% to 55 mol% SiO ₂ ; greater than or equal to 18 mol% Al ₂ O ₃ ; greater than or equal to 5 mol% MgO; greater than or equal to 2 mol% P ₂ O ₅ ; 0 mol% to 14 mol% ZnO; 0 mol% to 5 mol% TiO ₂ ; 0 mol% to 5 mol% Na ₂ O; 0 mol% to 5 mol% Li ₂ O; 0 mol% to 2 mol% BaO; 0 mol% to 4 mol% B ₂ O ₃ ; 0 mol% to 1 mol% CaO; 0 mol% to 3 mol% Eu ₂ O ₃ ; 0 mol% to 6 mol% Ta ₂ O ₅ ; 0 mol% to 5 mol% La ₂ O ₃ ; 0 mol% to 0.1 mol% As ₂ O ₅ ; and 0 mol% to 0.3 mol% SnO ₂ .

Additional features and advantages will be set forth in the detailed description that follows, and in part, will be apparent to those skilled in the art from the description, or may be learned by practice of the embodiments described herein, including the following: Detailed description, patent scope and drawings.

It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments described herein and, together with the description, serve to explain the principles and operations of the claimed subject matter.

Reference will now be made in detail to opaque zinc spinel-spinel glass ceramics according to various embodiments. In particular, opaque zinc spinel-spinel glass ceramics have high hardness and can be ion exchanged. Therefore, opaque zinc spinel-spinel glass ceramics are suitable for use as housings for portable electronic devices.

In the following description, like reference characters refer to similar or corresponding parts throughout the several figures shown in the drawings. It is also understood that terms such as "top," "bottom," "outward," "inward" and the like are terms of convenience and should not be construed as limiting terms, unless otherwise stated. Whenever a group is described as consisting of at least one element of a group of elements or a combination thereof, it is understood that the group may consist of any number of said elements, either alone or in combination with each other. Unless otherwise stated, ranges of values, when recited, include the upper and lower limits of the range and any range therebetween. Unless otherwise stated, the indefinite article "a" and the corresponding definite article "the" used herein mean "at least one" or "one or more". It should also be understood that the various features disclosed in the description and drawings may be used in any and all combinations.

Unless otherwise stated, all compositions of the glasses and glass-ceramics described herein are expressed in molar percentages (mol%) and ingredients are provided on an oxide basis. All temperatures are expressed in degrees Celsius (°C) unless otherwise stated.

Note that the terms "substantially" and "approximately" may be used herein to indicate the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement or other representation. These terms are also used herein to denote the extent to which a quantitative representation may differ from an established reference standard without resulting in a change in the essential functioning of the subject matter in question. For example, a glass that is "substantially free of K ₂ O" is one in which K ₂ O is not actively added or batch added to the glass, but may be present as a contaminant in very small amounts (e.g., in amounts less than about 0.01 mol%) Glass. As used herein, when the term "about" is used to modify a value, the exact value is also disclosed.

The glass ceramic contains a first crystalline phase, a second crystalline phase and a residual glass phase. The first crystalline phase may be the dominant crystalline phase, defined herein as the crystalline phase that accounts for the largest weight percent of the glass ceramic. Therefore, the second crystalline phase may be present in a weight percent of the glass ceramic that is less than the weight percent of the first crystalline phase. In some embodiments, the glass ceramic may include more than two crystalline phases.

In embodiments, the first crystalline phase includes (Mg _x Zn _1-x )Al ₂ O ₄ , where x is less than 1. _{The crystalline phase} ( _Mg In embodiments, x may be greater than or equal to 0, such as greater than or equal to about 0.1, greater than or equal to about 0.2, greater than or equal to about 0.3, greater than or equal to about 0.4, greater than or equal to about 0.5, greater than or equal to about 0.6, greater than or equal to about 0.7, greater than or equal to about 0.8, greater than or equal to about 0.9. In embodiments, x may be less than 1.0, such as less than or equal to about 0.9, less than or equal to about 0.8, less than or equal to about 0.7, less than or equal to about 0.6, less than or equal to about 0.5, less than or equal to about 0.4, less than or equal to About 0.3, less than or equal to about 0.2, less than or equal to about 0.1. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, x may be greater than or equal to 0 to less than 1.0, such as greater than or equal to about 0.1 to less than or equal to about 0.9, greater than or equal to about 0.2 to less than or equal to about 0.8, greater than or equal to about 0.3 to less than or equal to about 0.7, greater than or equal to about 0.4 to less than or equal to about 0.6, and all ranges and subranges therebetween.

The crystalline phase has crystallite size. The opacity of glass ceramics may be due, at least in part, to the large crystallite size. Unless otherwise stated, crystallite sizes used herein are determined by powder X-ray diffraction (XRD) analysis with scans from 5 to 80 degrees 2Θ. Crystallite size was estimated using the Scherrer equation function provided in MDI Jade, a software package for phase identification and quantitative analysis.

In embodiments, the second crystal phase includes at least one of tetragonal zirconia (ZrO ₂ ), MgTa ₂ O ₆ , mullite, and cordierite. The presence of secondary crystalline phases in glass ceramics may depend on the composition of the precursor glass and the ceramic process. The formation of tetragonal ZrO ₂ in glass ceramics requires the presence of ZrO ₂ in the precursor glass. Without wishing to be bound by any particular theory, it is believed that the tetragonal ZrO ₂ crystal phase crystallizes before the (Mg _x Zn _1-x )Al ₂ O ₄ crystal phase during ceramization and serves as the (Mg _x Zn _1-x )Al The nucleation site of _{the 2} O ₄ crystal phase. Additionally, without wishing to be bound by any particular theory, it is believed that any _TiO2 contained in the glass ceramic segregates into a tetragonal _ZrO2 phase and acts as a nucleating agent for the tetragonal _ZrO2 phase. When the precursor glass contains substantially no _ZrO , _MgTaO may be the _second crystalline phase. When the precursor glass contains little or no nucleating agent, secondary crystal phases of mullite and cordierite may be produced. In some embodiments, the composition of the precursor glass and the ceramization conditions may cause the glass-ceramic to include other crystalline phases than those described above.

In embodiments, the total crystallinity of the glass ceramic is high enough to provide enhanced mechanical properties such as hardness, Young's modulus, and scratch resistance. As used herein, total crystallinity is provided in wt% and refers to the sum of the wt% of all crystalline phases present in the glass-ceramic relative to the total weight of the glass-ceramic. In embodiments, the total crystallinity is greater than or equal to about 35 wt%, such as greater than or equal to about 40 wt%, greater than or equal to about 45 wt%, greater than or equal to about 50 wt%, greater than or equal to about 55 wt%, or bigger. In embodiments, the total crystallinity is less than or equal to about 60 wt%, such as less than or equal to about 55 wt%, less than or equal to about 50 wt%, less than or equal to about 45 wt%, less than or equal to about 40 wt%, or smaller. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass-ceramic has a total crystallinity of greater than or equal to about 35 wt% to less than or equal to about 60 wt%, such as greater than or equal to about 40 wt% to less than or equal to about 55 wt%, greater than or equal to about 45 wt % to less than or equal to about 50 wt%, and all ranges and subranges between the above values. The total crystallinity of the glass ceramic was determined by quantitative analysis of the XRD data collected as above by Rietveld. Rietveld analysis uses the least squares method to model the XRD data and then determines the phase concentration in the sample based on the known lattice and scaling factors of the identified phases.

Glass ceramics are opaque in the visible range. As used herein, a glass ceramic is considered opaque when it exhibits less than 50% transmission in the visible range (380 nm to 760 nm). Transmittance, as used herein refers to total transmittance, was measured on a Perkin Elmer Lambda 950 UV/VIS/NIR spectrophotometer with a 150 mm integrating sphere. Mount the sample in the entrance port of the sphere and allow for collection of scattered light over a wide angle. Total transmittance data were collected at the outlet of the sphere by reference to a Spectralon reflectance disk. The percentage of total transmission (%T) was calculated relative to the open beam baseline measurement. In embodiments, the glass-ceramic has a transmittance in the visible range of less than 50%, such as less than or equal to about 45%, less than or equal to about 40%, less than or equal to about 35%, less than or equal to about 30%, or less .

In embodiments, the glass ceramic appears white. In embodiments, the glass ceramic may be colorless or substantially colorless. As used herein, essentially colorless refers to the following color coordinate space: L* >90, a* from -0.2 to 0.2, and b* from -0.1 to 0.6. Color coordinates were measured using a UV/Vis/NIR spectrophotometer equipped with an integrating sphere. Measurements were performed in the wavelength range from 380 nm to 770 nm at 2 nm intervals with light source D65, observer A and F2 at 10°. The process of determining the color space in a CIE system is described in more detail in "Standard practice for computing the colors of objects by using the CIR system" (ASTM E308-08).

In embodiments, the glass ceramic may have a hardness that renders the glass ceramic less susceptible to damage, such as by increasing scratch resistance. As used herein, unless otherwise stated, hardness is measured with a nanoindenter and is presented in GPa. Measurements of the nanoindenter were performed using a rhombus Berkovich tip using the continuum stiffness method used with the Agilent G200 nanoindenter. The continuous stiffness method utilizes a small sinusoidal displacement signal (1 nm amplitude at 45 Hz, superimposed on the tip when loaded onto the sample surface) and continuously determines load, depth and contact stiffness. Without wishing to be bound by any particular theory, it is believed that the hardness of the glass ceramic is due, at least in part, to the hardness of (Mg _x Zn _1-x )Al ₂ O ₄ and secondary crystalline phases contained therein, such as tetragonal ZrO ₂ .

In embodiments, the glass ceramic has a hardness greater than or equal to about 7.5 GPa, such as greater than or equal to about 7.6 GPa, greater than or equal to about 7.7 GPa, greater than or equal to about 7.8 GPa, greater than or equal to about 7.9 GPa, greater than or equal to about 8.0 GPa, greater than or equal to about 8.1 GPa, greater than or equal to about 8.2 GPa, greater than or equal to about 8.3 GPa, greater than or equal to about 8.4 GPa, greater than or equal to about 8.5 GPa, greater than or equal to about 8.6 GPa, greater than or equal to about 8.7 GPa , greater than or equal to about 8.8 GPa, greater than or equal to about 8.9 GPa, greater than or equal to about 9.0 GPa, greater than or equal to about 9.1 GPa, greater than or equal to about 9.2 GPa, greater than or equal to about 9.3 GPa, greater than or equal to about 9.4 GPa, Greater than or equal to about 9.5 GPa, greater than or equal to about 9.6 GPa, greater than or equal to about 9.7 GPa, greater than or equal to about 9.8 GPa, greater than or equal to about 9.9 GPa, greater than or equal to about 10.0 GPa, greater than or equal to about 10.1 GPa, greater than or equal to about 10.2 GPa, greater than or equal to about 10.3 GPa, greater than or equal to about 10.4 GPa, greater than or equal to about 10.5 GPa, greater than or equal to about 10.6 GPa, greater than or equal to about 10.7 GPa, greater than or equal to about 10.8 GPa, greater than or Equal to about 10.9 GPa, greater than or equal to about 11.0 GPa, greater than or equal to about 11.1 GPa, greater than or equal to about 11.2 GPa, greater than or equal to about 11.3 GPa, greater than or equal to about 11.4 GPa, greater than or equal to about 11.5 GPa, greater than or equal to About 11.6 GPa, greater than or equal to about 11.7 GPa, greater than or equal to about 11.8 GPa, greater than or equal to about 11.9 GPa, greater than or equal to about 12.0 GPa, greater than or equal to 12.1 GPa, greater than or equal to about 12.2 GPa, greater than or equal to about 12.3 GPa, greater than or equal to about 12.4 GPa, greater than or equal to about 12.5 GPa, greater than or equal to about 12.6 GPa, greater than or equal to about 12.7 GPa, greater than or equal to about 12.8 GPa, greater than or equal to about 12.9 GPa, or greater. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass ceramic has a hardness of greater than or equal to about 7.5 GPa to less than or equal to about 13.0 GPa, such as greater than or equal to about 8.0 GPa to less than or equal to about 12.5 GPa, greater than or equal to about 8.5 GPa to less than or equal to about 12.0 GPa, greater than or equal to about 9.0 GPa to less than or equal to about 11.5 GPa, greater than or equal to about 9.5 GPa to less than or equal to about 11.0 GPa, greater than or equal to about 10.0 GPa to less than or equal to about 10.5 GPa, and values in between All ranges and subranges.

The Young's modulus of the glass ceramic according to embodiments may be greater than or equal to about 90.0 GPa, such as greater than or equal to about 92.0 GPa, greater than or equal to about 94.0 GPa, greater than or equal to about 96.0 GPa, greater than or equal to about 98.0 GPa, greater than or equal to Equal to about 100.0 GPa, greater than or equal to about 102.0 GPa, greater than or equal to about 104.0 GPa, greater than or equal to about 106.0 GPa, greater than or equal to about 108.0 GPa, greater than or equal to about 110.0 GPa, greater than or equal to about 112.0 GPa, greater than or equal to About 114.0 GPa, greater than or equal to about 116.0 GPa, greater than or equal to about 118.0 GPa, greater than or equal to about 120.0 GPa, greater than or equal to 122.0 GPa, greater than or equal to 124.0 GPa, or greater. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass ceramic has a Young's modulus of greater than or equal to about 90.0 GPa to less than or equal to about 125.0 GPa, such as greater than or equal to about 92.0 GPa to less than or equal to about 123.0 GPa, greater than or equal to about 94.0 GPa to less than or Equal to about 121.0 GPa, greater than or equal to about 96.0 GPa to less than or equal to about 119.0 GPa, greater than or equal to about 98.0 GPa to less than or equal to about 117.0 GPa, greater than or equal to about 100.0 GPa to less than or equal to about 115.0 GPa, greater than or equal to About 102.0 GPa to less than or equal to about 113.0 GPa, greater than or equal to about 104.0 GPa to less than or equal to about 111.0 GPa, greater than or equal to about 106.0 GPa to less than or equal to about 109.0 GPa, greater than or equal to about 107.0 GPa to less than or equal to about 108.0 GPa, and all ranges and subranges between the above values. Unless otherwise stated, Young's modulus values reported in this disclosure refer to values measured by the general type of resonant ultrasonic spectroscopy technique set forth in ASTM E2001-13 and expressed in GPa, entitled "Standard Guide" for Resonant Ultrasound Spectroscopy for Defect Detection in Both Metallic and Non-metallic Parts".

Glass-ceramics may have sufficiently high strain points and annealing points to permit additional processing of the glass-ceramic at temperatures up to about 800°C without adversely affecting the structural integrity of the glass-ceramic. This additional treatment may include chemical enhancements such as ion exchange. These elevated processing temperatures may increase the efficiency of the additional processing, for example by reducing the time required for the additional processing. In embodiments, the strain point may be less than or equal to about 900°C, such as greater than or equal to about 700°C to less than or equal to about 900°C. These strain points allow for improved thermal stability and a larger potential temperature range for ion exchange processing. If the strain point is too low, additional processing of the glass ceramic may become difficult. If the strain point is too high, fabrication of the precursor glass composition may become difficult.

The composition of the opaque zinc spinel-spinel glass ceramic will now be described. In the examples of glass ceramics described herein, unless otherwise stated, the compositional components (such as SiO ₂ , Al ₂ O ₃ , Li ₂ O, Na ₂ O etc.) concentration. The components of the glass ceramics according to the embodiments are discussed separately below. It is to be understood that any of the various recited ranges for one component may be combined individually with any of the various recited ranges for any other component.

In the embodiments of the glass ceramics disclosed herein, _SiO2 is the largest component. Pure _SiO2 has a relatively low CTE and is alkaline-free. However, pure _SiO2 has a high melting point. Therefore, if the concentration of _SiO2 in the glass ceramic is too high, the formability of the precursor glass composition used to form the glass ceramic may be reduced because the higher _SiO2 concentration will increase the difficulty of melting the glass, which in turn will affect the precursor Adversely affects the formability of physical glass. In embodiments, the glass composition includes an amount of _SiO2 generally greater than or equal to about 35.0 mol%, such as greater than or equal to about 40.0 mol%, greater than or equal to about 45.0 mol%, greater than or equal to about 50.0 mol%, greater than or equal to about 55.0 mol%, or greater. In embodiments, the glass composition includes an _amount of SiO less than or equal to about 60.0 mol%, such as less than or equal to about 55.0 mol%, less than or equal to about 50.0 mol%, less than or equal to about 45.0 mol%, less than or equal to about 40.0 mol% mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass composition includes an amount of _SiO2 from greater than or equal to about 35.0 mol% to less than or equal to about 60.0 mol%, such as greater than or equal to about 35.0 mol% to less than or equal to about 55.0 mol%, greater than or equal to about 40.0 mol% mol% to less than or equal to about 50.0 mol%, about 45.0 mol%, and all ranges and subranges therebetween.

The glass ceramics of embodiments may further contain Al ₂ O ₃ . Since Al ₂ O ₃ has a tetrahedral coordination relationship in the glass melt formed from the glass composition, it may increase the viscosity of the precursor glass composition used to form the glass ceramic, and when the content of Al ₂ O ₃ is excessive When high, the formability of the glass composition will be reduced. However, when the concentration of Al ₂ O ₃ in the glass composition reaches equilibrium with the concentration of SiO ₂ and the concentration of alkali metal oxides, Al ₂ O ₃ can reduce the liquidus temperature of the glass melt, thereby increasing the liquidus viscosity And improve the compatibility of the glass composition with certain forming processes (eg, melt forming processes). When the precursor glass is ceramized to form a glass ceramic, the Al ₂ O ₃ in the precursor glass also provides the aluminum needed to form the zinc spinel-spinel crystal phase. In embodiments, the glass composition includes an Al ₂ O ₃ concentration generally greater than or equal to about 18.0 mol %, such as greater than or equal to about 19.0 mol %, greater than or equal to about 20.0 mol %, greater than or equal to about 21.0 mol %, greater than or equal to Equal to about 22.0 mol%, greater than or equal to about 23.0 mol%, greater than or equal to about 24.0 mol%, greater than or equal to about 25.0 mol%, or greater. In embodiments, the glass composition includes an amount of Al ₂ O ₃ less than or equal to about 26.0 mol %, such as less than or equal to about 25.0 mol %, less than or equal to about 24.0 mol %, less than or equal to about 23.0 mol %, less than or equal to About 22.0 mol%, less than or equal to about 21.0 mol%, less than or equal to about 20.0 mol%, less than or equal to about 19.0 mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass composition includes an Al ₂ O ₃ amount greater than or equal to about 18.0 mol% to less than or equal to about 26.0 mol%, such as greater than or equal to about 19.0 mol% to less than or equal to about 25.0 mol%, greater than or equal to About 20.0 mol% to less than or equal to about 24.0 mol%, greater than or equal to about 21.0 mol% to less than or equal to about 23.0 mol%, about 22.0 mol%, and all ranges and subranges in between.

The glass ceramics of embodiments may further contain ZnO. When the precursor glass is ceramized to form a glass ceramic, the ZnO in the precursor glass provides the zinc required to form the zinc spinel-spinel crystal phase. In embodiments, the glass composition includes a ZnO concentration typically greater than or equal to 0 mol%, such as greater than or equal to about 1.0 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 3.0 mol%, greater than or equal to about 4.0 mol% %, greater than or equal to about 5.0 mol%, greater than or equal to about 6.0 mol%, greater than or equal to about 7.0 mol%, greater than or equal to about 8.0 mol%, greater than or equal to about 9.0 mol%, greater than or equal to about 10.0 mol%, Greater than or equal to about 11.0 mol%, greater than or equal to about 12.0 mol%, greater than or equal to about 13.0 mol%, or greater. In embodiments, the glass composition includes an amount of ZnO less than or equal to about 15.0 mol%, such as less than or equal to about 14.0 mol%, less than or equal to about 13.0 mol%, less than or equal to about 12.0 mol%, less than or equal to about 11.0 mol% %, less than or equal to about 10.0 mol%, less than or equal to about 9.0 mol%, less than or equal to about 8.0 mol%, less than or equal to about 7.0 mol%, less than or equal to about 6.0 mol%, less than or equal to about 5.0 mol%, Less than or equal to about 4.0 mol%, less than or equal to about 3.0 mol%, less than or equal to about 2.0 mol%, less than or equal to about 1.0 mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass composition includes an amount of ZnO from greater than 0 mol% to less than or equal to about 15.0 mol%, such as greater than or equal to about 1.0 mol% to less than or equal to about 14.0 mol%, greater than or equal to about 2.0 mol% to less than Or equal to about 13.0 mol%, greater than or equal to about 3.0 mol% to less than or equal to about 12.0 mol%, greater than or equal to about 4.0 mol% to less than or equal to about 11.0 mol%, greater than or equal to about 5.0 mol% to less than or equal to About 10.0 mol%, greater than or equal to about 6.0 mol% to less than or equal to about 9.0 mol%, greater than or equal to about 7.0 mol% to less than or equal to about 8.0 mol%, and all ranges and subranges therebetween.

The glass ceramics of embodiments may further contain MgO. When the precursor glass is ceramized to form a glass ceramic, the MgO in the precursor glass provides the magnesium needed to form a spinel solid solution containing the crystalline phase. In embodiments, the amount of MgO in the glass ceramic is greater than or equal to about 5.0 mol%, such as greater than or equal to about 6.0 mol%, greater than or equal to about 7.0 mol%, greater than or equal to about 8.0 mol%, greater than or equal to about 9.0 mol% %, greater than or equal to about 10.0 mol%, greater than or equal to about 11.0 mol%, greater than or equal to about 12.0 mol%, greater than or equal to about 13.0 mol%, greater than or equal to about 14.0 mol%, greater than or equal to about 15.0 mol%, or larger. In embodiments, the amount of MgO in the glass ceramic is less than or equal to about 16.0 mol%, such as less than or equal to about 15.0 mol%, less than or equal to about 14.0 mol%, less than or equal to about 13.0 mol%, less than or equal to about 12.0 mol% %, less than or equal to about 11.0 mol%, less than or equal to about 10.0 mol%, less than or equal to about 9.0 mol%, less than or equal to about 8.0 mol%, less than or equal to about 7.0 mol%, less than or equal to about 6.0 mol%, or smaller. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the amount of MgO in the glass ceramic is greater than or equal to about 5.0 mol% to less than or equal to about 16.0 mol%, such as greater than or equal to about 6.0 mol% to less than or equal to about 15.0 mol%, greater than or equal to about 7.0 mol% % to less than or equal to about 14.0 mol%, greater than or equal to about 8.0 mol% to less than or equal to about 13.0 mol%, greater than or equal to about 9.0 mol% to less than or equal to about 12.0 mol%, greater than or equal to about 10.0 mol% to Less than or equal to about 11.0 mol%, and all ranges and subranges between the above values. In embodiments where the ratio of MgO to ZnO in the glass ceramic is high, the opacity of the glass ceramic is enhanced.

The glass ceramics of embodiments may further contain CaO. In embodiments, the amount of CaO in the glass ceramic is greater than or equal to 0 mol% to less than or equal to about 1.0 mol%, such as greater than or equal to about 0.1 mol% to less than or equal to about 0.9 mol%, greater than or equal to about 0.2 mol% to less than or equal to about 0.8 mol%, greater than or equal to about 0.3 mol% to less than or equal to about 0.7 mol%, greater than or equal to about 0.4 mol% to less than or equal to about 0.6 mol%, about 0.5 mol%, and any of the above values all ranges and subranges in between.

The glass ceramic may further contain P ₂ O ₅ . The inclusion of P ₂ O ₅ can enhance the ion exchange capacity of glass ceramics. In embodiments, the glass ceramic may comprise an amount _{of P2O5} greater than or equal to about 2.0 mol%, such as greater than or equal to about 2.5 mol% _P2O5 , greater than or equal to about 3.0 mol%, greater than or equal to about 3.5 mol _% %, greater than or equal to about 4.0 mol%, greater than or equal to about 4.5 mol%, greater than or equal to about 5.0 mol%, or greater. In embodiments, the glass-ceramic may comprise P ₂ O ₅ in an amount from greater than or equal to about 2.0 mol% to less than or equal to about 6.0 mol%, such as greater than or equal to about 2.5 mol% to less than or equal to about 5.5 mol%, greater than or equal to Equal to about 3.0 mol% to less than or equal to about 5.0 mol%, greater than or equal to about 3.5 mol% to less than or equal to about 4.5 mol%, about 2.0 mol%, and all ranges and subranges in between.

The glass ceramics of embodiments may further comprise B ₂ O ₃ . B ₂ O ₃ can increase the natural damage resistance of the precursor glass. In embodiments, _the glass composition includes an amount of _B2O3 from greater than or equal to 0 mol% to less than or equal to about 4.0 mol%, such as greater than or equal to about 0.5 mol% to less than or equal to about 3.5 mol%, greater than or equal to about 1.0 mol% to less than or equal to about 3.0 mol%, greater than or equal to about 1.5 mol% to less than or equal to about 2.5 mol%, about 2.0 mol%, and all ranges and subranges therebetween.

The glass ceramics of embodiments may further comprise a nucleating agent. Nucleating agents can form nuclei in the precursor glass used to form the glass ceramic. In some embodiments, the nucleating agent allows ceramization of the glass ceramic without the need for a separate nucleation step. The nucleating agent can be selected from ZrO ₂ , TiO ₂ , Eu ₂ O ₃ , Ta ₂ O ₅ , and La ₂ O ₃ . In embodiments, the total amount of nucleating agent in the glass ceramic may be an amount greater than or equal to 0 mol%, such as greater than or equal to about 1.0 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 3.0 mol%, Greater than or equal to about 4.0 mol%, greater than or equal to about 5.0 mol%, or greater. In embodiments, the total amount of nucleating agent in the glass ceramic may be an amount greater than or equal to about 6.0 mol%, such as less than or equal to about 5.0 mol%, less than or equal to about 4.0 mol%, less than or equal to about 3.0 mol% %, less than or equal to about 2.0 mol%, less than or equal to about 1.0 mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the total amount of nucleating agent in the glass ceramic may be an amount greater than or equal to 0 mol% to less than or equal to about 6.0 mol%, such as an amount greater than or equal to about 1.0 mol% to less than or equal to about 5.0 mol% , greater than or equal to about 2.0 mol% to less than or equal to about 4.0 mol%, greater than or equal to about 1.0 mol% to less than or equal to about 3.0 mol%, about 2.0 mol%, and all ranges and subranges between the above values. In some embodiments, the glass ceramic may contain less than or equal to about 5.5 mol% of the nucleating agent and additionally contain at least one of La ₂ O ₃ , Ta ₂ O ₅ and greater than or equal to about 2 mol% Li ₂ O. In some embodiments, the glass-ceramic may contain less than or equal to about 5.1 mol % nucleating agent and further contain less than 2 mol % Li ₂ O and be substantially free of La ₂ O ₃ and Ta ₂ O ₅ .

In embodiments, the glass ceramic may comprise Eu ₂ O ₃ in an amount from greater than or equal to 0 mol % to less than or equal to about 3.0 mol %, such as in an amount greater than or equal to about 0.5 mol % to less than or equal to about 2.5 mol %, greater than or equal to equal to about 1.0 mol% to less than or equal to about 2.0 mol%, about 1.5 mol%, and all ranges and subranges in between.

In embodiments, the glass ceramic may comprise Ta ₂ O ₅ in an amount from greater than or equal to 0 mol % to less than or equal to about 6.0 mol %, such as in an amount greater than or equal to about 1.0 mol % to less than or equal to about 5.0 mol %, greater than or equal to Equal to about 2.0 mol% to less than or equal to about 4.0 mol%, greater than or equal to about 1.0 mol% to less than or equal to about 3.0 mol%, about 2.0 mol%, and all ranges and subranges in between.

In embodiments, the glass ceramic may comprise La ₂ O ₃ in an amount greater than or equal to 0 mol % to less than or equal to about 5.0 mol %, such as in an amount greater than or equal to about 1.0 mol % to less than or equal to about 4.0 mol %, greater than or equal to equal to about 2.0 mol% to less than or equal to about 3.0 mol%, and all ranges and subranges in between.

In embodiments, the glass ceramic may contain _ZrO as the sole nucleating agent. In addition to acting as a nucleating agent, the presence of _ZrO in the precursor glass also facilitates the crystallization of tetragonal _ZrO during the ceramization process. The use of _ZrO as the sole nucleating agent in the precursor glass composition can produce glass ceramics that are colorless in appearance. In embodiments, the _{amount of} ZrO in the glass ceramic is greater than 0 mol%, such as greater than or equal to about 1.0 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 3.0 mol%, greater than or equal to about 4.0 mol%, Greater than or equal to about 5.0 mol%, greater than or equal to about 6.0 mol%, greater than or equal to about 7.0 mol%, greater than or equal to about 8.0 mol%, or greater than or equal to about 9.0 mol%. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the _amount of ZrO in the glass ceramic is greater than 0 mol% to less than or equal to about 10.0 mol%, such as greater than or equal to about 1.0 mol% to less than or equal to about 9.0 mol%, greater than or equal to about 2.0 mol% to Less than or equal to about 8.0 mol%, greater than or equal to about 3.0 mol% to less than or equal to about 7.0 mol%, or greater than or equal to about 4.0 mol% to less than or equal to about 6.0 mol%, and all ranges and subdivisions in between. Scope.

In embodiments, the glass ceramic may include _TiO2 as a nucleating agent. _TiO2 is an effective nucleating agent. However, when the amount of _TiO2 in the precursor glass is too high, the resulting glass ceramic may have an undesirable colored appearance. Glass-ceramics containing _TiO2 may have a yellow or brown appearance in the visible range. Without wishing to be bound by any particular theory, it is believed that reduction of Ti ⁴⁺ to Ti ³⁺ produces the colored appearance of the glass ceramic. In embodiments, the amount of _TiO2 in the glass ceramic is greater than or equal to 0 mol%, such as greater than or equal to about 1.0 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 3.0 mol%, greater than or equal to about 4.0 mol% %, or greater. In embodiments, the amount of _TiO2 in the glass ceramic is less than or equal to about 5.0 mol%, such as less than or equal to about 4.0 mol%, less than or equal to about 3.0 mol%, less than or equal to about 2.0 mol%, less than or equal to about 1.0 mol% mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass ceramic has _{an amount of} TiO in the glass ceramic from greater than or equal to 0 mol% to less than or equal to about 5.0 mol%, such as greater than or equal to about 1.0 mol% to less than or equal to about 4.0 mol%, or greater than or equal to From about 2.0 mol% to less than or equal to about 3.0 mol%, and all ranges and subranges therebetween. In embodiments, the glass ceramic is substantially free or free of _TiO2 .

Glass-ceramics may include one or more alkali metal oxides. Alkali metal oxides contribute to the chemical strengthening of glass ceramics, for example by ion exchange processes. The sum of alkali metal oxides (such as Li ₂ O, Na ₂ O, and K ₂ O and other alkali metal oxides including Cs ₂ O and Rb ₂ O) in the glass ceramic may be referred to as "R ₂ O", and R ₂ O can be expressed in mol%. In some embodiments, the glass ceramic may include a mixture of alkali metal oxides, such as a combination of Li ₂ O and Na ₂ O, a combination of Na ₂ O and K ₂ O, a combination of Li ₂ O and K ₂ O, or Li Combination of ₂ O, Na ₂ O and K ₂ O. In embodiments, the glass ceramic includes at least one of Li ₂ O and Na ₂ O. The inclusion of mixtures of alkali metal oxides in glass ceramics may lead to faster and more efficient ion exchange. Without wishing to be bound by any particular theory, it is believed that the alkali metal oxides segregate into the residual glass phase of the glass ceramic after ceramization.

The addition of lithium to the glass ceramic enables the ion exchange process and further reduces the softening point of the precursor glass composition. In embodiments, the glass composition includes an amount of _Li2O typically greater than or equal to 0 mol%, such as greater than or equal to about 0.5 mol%, greater than or equal to about 1.0 mol%, greater than or equal to about 1.5 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 2.5 mol%, greater than or equal to about 3.0 mol%, greater than or equal to about 3.5 mol%, greater than or equal to about 4.0 mol%, greater than or equal to about 4.5 mol%, or greater. In some embodiments, the glass composition includes an amount of _Li2O less than or equal to about 5.0 mol%, such as less than or equal to about 4.5 mol%, less than or equal to about 4.0 mol%, less than or equal to about 3.5 mol%, less than or equal to About 3.0 mol%, less than or equal to about 2.5 mol%, less than or equal to about 2.0 mol%, less than or equal to about 1.5 mol%, less than or equal to about 1.0 mol%, less than or equal to about 0.5 mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass composition includes an amount of _Li2O from greater than or equal to 0.0 mol% to less than or equal to about 5.0 mol%, such as greater than or equal to about 0.5 mol% to less than or equal to about 4.5 mol%, greater than or equal to about 1.0 mol% to less than or equal to 4.0 mol%, greater than or equal to about 1.5 mol% to less than or equal to about 3.5 mol%, greater than or equal to about 2.0 mol% to less than or equal to about 3.0 mol%, about 2.5 mol%, and the above values all ranges and subranges in between.

Like Li ₂ O, Na ₂ O contributes to the ion exchangeability of the glass ceramic and also reduces the melting point of the precursor glass composition and improves the formability of the precursor glass composition. In embodiments, the glass composition includes an amount of _Na2O typically greater than or equal to 0 mol%, such as greater than or equal to about 0.5 mol%, greater than or equal to about 1.0 mol%, greater than or equal to about 1.5 mol%, greater than or equal to about 2.0 mol%, greater than or equal to about 2.5 mol%, greater than or equal to about 3.0 mol%, greater than or equal to about 3.5 mol%, greater than or equal to about 4.0 mol%, greater than or equal to about 4.5 mol%, or greater. In some embodiments, the glass composition includes an amount of _Na2O less than or equal to about 5.0 mol%, such as less than or equal to about 4.5 mol%, less than or equal to about 4.0 mol%, less than or equal to about 3.5 mol%, less than or equal to About 3.0 mol%, less than or equal to about 2.5 mol%, less than or equal to about 2.0 mol%, less than or equal to about 1.5 mol%, less than or equal to about 1.0 mol%, less than or equal to about 0.5 mol%, or less. It should be understood that, in embodiments, any of the above ranges may be combined with any other range. In embodiments, the glass composition includes an amount of Na ₂ O from greater than or equal to 0.0 mol% to less than or equal to about 5.0 mol%, such as greater than or equal to about 0.5 mol% to less than or equal to about 4.5 mol%, greater than or equal to about 1.0 mol% to less than or equal to 4.0 mol%, greater than or equal to about 1.5 mol% to less than or equal to about 3.5 mol%, greater than or equal to about 2.0 mol% to less than or equal to about 3.0 mol%, about 2.5 mol%, and the above values all ranges and subranges in between.

In embodiments, the glass ceramic may additionally include BaO. The inclusion of BaO in glass ceramics increases the refractive index of the residual glass phase in the glass ceramics. BaO can be added to the glass melt in the form of carbonates and nitrates to maintain the oxidation state of the system during the melting process and prevent Ti ⁴⁺ from being reduced to Ti ³⁺ when TiO ₂ is present in the composition. BaO can be used to prevent undesirable coloration of glass ceramics due to the presence of _TiO2 . In embodiments, the glass ceramic may comprise BaO in an amount from greater than or equal to 0 mol% to less than or equal to about 2.0 mol%, such as greater than or equal to about 0.5 mol% to less than or equal to about 1.5 mol%, about 1.0 mol%, and All ranges and subranges between the above values.

In embodiments, the glass ceramic may optionally include one or more fining agents. In some embodiments, the fining agent may include, for example, tin oxide (SnO ₂ ) and/or arsenic oxide. In embodiments, the amount of _SnO2 present in the glass composition is less than or equal to 0.3 mol%, such as greater than or equal to 0 mol% and less than or equal to 0.3 mol%, greater than or equal to 0.1 mol% to less than or equal to 0.2 mol%, and All ranges and subranges between the above values. In embodiments, arsenic oxide is present in the glass ceramic in an amount greater than or equal to 0 mol% and less than or equal to 0.1 mol%, and all ranges and subranges in between. In embodiments, arsenic oxide may also be used as a bleaching agent. In embodiments, the glass ceramic may be free or substantially free of one or both arsenic and antimony.

In summary, glass ceramics according to embodiments may be formed from precursor glass articles formed by any suitable method, such as slot forming, float forming, rolling processes, fusion forming processes, and the like.

Precursor glass articles may be characterized by the manner in which they are formed. For example, precursor glass articles may be characterized as being float-formable (i.e., formed by a float process), down-stretchable, and particularly fusion-formable, or slit-stretchable (i.e., formed by a fusion-draw process such as Or formed by the downward stretching process of the slot stretching process).

Some embodiments of the precursor glass articles described herein may be formed by a down-draw process. The down-draw process produces a glass article of uniform thickness with a relatively pristine surface. Since the average flexural strength of a glass article is controlled by the number and size of surface defects, the original surface with the least contact has a higher initial strength. Additionally, drop-down glass products have a very flat, smooth surface that can be used in final applications without the need for expensive grinding and polishing.

Some embodiments of precursor glass articles may be described as fusion-formable (i.e., may be formed using a fusion draw process). The fusion process uses a drawing tank with a channel for receiving molten glass feedstock. The weirs of the channel are open at the top along the length of the channel on both sides of the channel. As the channel fills with molten material, the molten glass overflows over the weir. Due to gravity, the molten glass flows downward to the outer surface of the stretching tank as two flowing glass films. These outer surfaces of the stretch groove extend downwardly and inwardly so that they join at the lower edge of the stretch groove. Two flowing glass membranes join at this edge to fuse and form a single flowing glass article. The fusion stretching method offers the advantage that since the two glass films flowing over the channel are fused together, the outer surface of the resulting glass article does not come into contact with any part of the device. Therefore, the surface properties of the fused-stretched glass article are not affected by the contact described above.

Some embodiments of the precursor glass articles described herein may be formed by a slot drawing process. The slot drawing process is different from the fusion drawing method. In the slot stretching process, molten raw glass is supplied to the stretching tank. The bottom of the stretching tank has an open slot with a nozzle extending the length of the slot. The molten glass flows through the slot/nozzle and is pulled down into the annealing zone as a continuous glass article.

Glass ceramics can be formed by ceramizing a precursor glass under any suitable conditions. In order to form crystal nuclei in the precursor glass, ceramization does not necessarily include a separate nucleation process. The ability to produce transparent glass ceramics without a separate nucleation step reduces the complexity of the production process and saves energy and time. In some embodiments, including a nucleation process may allow additional control over the size of the resulting crystallites.

In embodiments, ceramization occurs at a temperature greater than or equal to about 750°C, such as greater than or equal to about 800°C, greater than or equal to about 850°C, greater than or equal to about 900°C, greater than or equal to about 950°C, greater than or equal to about 1000°C, greater than or equal to about 1050°C, greater than or equal to about 1100°C, or greater. In embodiments, ceramization occurs at a temperature greater than or equal to about 750°C to less than or equal to about 1100°C, such as greater than or equal to about 800°C to less than or equal to about 1050°C, greater than or equal to about 850°C to less than or equal to about 1000°C, or greater than or equal to about 900°C to less than or equal to about 950°C, and all ranges and subranges therebetween.

In embodiments, the ceramization duration is greater than or equal to about 30 minutes, such as greater than or equal to about 1.0 hours, greater than or equal to about 1.5 hours, greater than or equal to about 2.0 hours, greater than or equal to about 2.5 hours, greater than or equal to about 3.0 hours, greater than or equal to about 3.5 hours, greater than or equal to about 4.0 hours, greater than or equal to about 4.5 hours, greater than or equal to about 5.0 hours, greater than or equal to about 5.5 hours, greater than or equal to about 6.0 hours, greater than or equal to about 6.5 hours , greater than or equal to about 7.0 hours, greater than or equal to about 7.5 hours, greater than or equal to about 8.0 hours, greater than or equal to about 8.5 hours, greater than or equal to about 9.0 hours, greater than or equal to about 9.5 hours, greater than or equal to about 10.0 hours, Greater than or equal to about 10.5 hours, greater than or equal to about 11.0 hours, greater than or equal to about 11.5 hours, greater than or equal to about 12.0 hours, greater than or equal to about 12.5 hours, greater than or equal to about 13.0 hours, greater than or equal to about 13.5 hours, greater than or equal to about 14.0 hours, greater than or equal to about 14.5 hours, greater than or equal to about 15.0 hours, greater than or equal to about 15.5 hours, greater than or equal to about 16.0 hours, greater than or equal to about 16.5 hours, greater than or equal to about 17.0 hours, greater than or Equal to about 17.5 hours, greater than or equal to about 18.0 hours, greater than or equal to about 18.5 hours, greater than or equal to about 19.0 hours, greater than or equal to about 19.5 hours, greater than or equal to about 20.0 hours, greater than or equal to about 20.5 hours, greater than or equal to About 21.0 hours, greater than or equal to about 21.5 hours, greater than or equal to about 22.0 hours, greater than or equal to about 22.5 hours, greater than or equal to about 23.0 hours, or greater than or equal to about 23.5 hours. In embodiments, the ceramization duration is greater than or equal to about 30 minutes to less than or equal to about 24.0 hours, such as greater than or equal to about 1.0 hours to less than or equal to about 23.0 hours, greater than or equal to about 1.5 hours to less than or equal to about 22.0 hours hours, greater than or equal to about 2.0 hours to less than or equal to about 21.0 hours, greater than or equal to about 2.5 hours to less than or equal to about 20.0 hours, greater than or equal to about 3.0 hours to less than or equal to about 19.0 hours, greater than or equal to about 3.5 hours to less than or equal to about 18.0 hours, greater than or equal to about 4.0 hours to less than or equal to about 17.0 hours, greater than or equal to about 4.5 hours to less than or equal to about 16.0 hours, greater than or equal to about 5.0 hours to less than or equal to about 15.0 hours, Greater than or equal to about 5.5 hours to less than or equal to about 14.0 hours, greater than or equal to about 6.0 hours to less than or equal to about 13.0 hours, greater than or equal to about 6.5 hours to less than or equal to about 12.0 hours, greater than or equal to about 7.0 hours to less than or equal to about 11.0 hours, greater than or equal to about 7.5 hours to less than or equal to about 10.0 hours, or greater than or equal to about 8.0 hours to less than or equal to about 9.0 hours, and all ranges and subranges between the above values.

In embodiments that include a separate nucleation process, the nucleation process occurs at a temperature greater than or equal to about 700°C, such as greater than or equal to about 750°C, greater than or equal to about 800°C, greater than or equal to about 850°C, greater than or equal to about 900°C, greater than or equal to about 950°C, or greater than or equal to about 1000°C, or greater. In embodiments, the nucleation process occurs at a temperature greater than or equal to about 700°C to less than or equal to about 1000°C, such as greater than or equal to about 750°C to less than or equal to about 950°C, or greater than or equal to about 800°C to less than or equal to approximately 900°C, and all ranges and subranges between the above values.

In embodiments, the duration of the nucleation treatment is greater than 0 minutes, such as greater than or equal to about 30 minutes, greater than or equal to about 1.0 hours, greater than or equal to about 1.5 hours, greater than or equal to about 2.0 hours, greater than or equal to about 2.5 hours , greater than or equal to about 3.0 hours, greater than or equal to about 3.5 hours, greater than or equal to about 4.0 hours, or greater. In embodiments, the duration of ceramization is greater than or equal to about 30 minutes to less than or equal to about 4.0 hours, such as greater than or equal to about 1.0 hours to less than or equal to about 3.5 hours, or greater than or equal to about 1.5 hours to less than or equal to Approximately 3.0 hours, and all ranges and subranges between the above values.

In embodiments, ceramization can be performed by irradiating the precursor glass with a laser. The use of a laser allows for the localized ceramization of areas or portions of the precursor glass article that may create residual stresses and strains in the glass ceramic. Stress and tension can then create areas of glass-ceramic articles with increased mechanical strength, such as the edges of casings or backplates used in mobile electronic devices. In embodiments, the laser used in the ceramization process may be a carbon dioxide laser. In addition, the use of lasers in the ceramization process can form patterns of ceramic areas in glass ceramics.

In embodiments, the glass ceramic can also be chemically strengthened through ion exchange or other methods to produce a glass ceramic that is resistant to damage for applications such as but not limited to display covers. Referring to Figure 1, a glass ceramic has a first region (eg, first and second compressive layers 120, 122 in Figure 1) extending from a surface of the glass ceramic to a depth of compression (DOC) under compressive stress and under tensile stress A second region under or center tension (CT) extends from the DOC to the center or interior region of the glass ceramic (eg, center region 130 in Figure 1). As used herein, DOC refers to the depth at which the stress within the glass ceramic changes from compression to tension. At the DOC, the stress passes from positive (compressive) stress to negative (tensile) stress, so the stress value here is zero.

According to the convention commonly used in the art, compressive or compressive stress is expressed as negative (>0) stress, while tensile or tensile stress is expressed as positive (>0) stress. However, throughout this specification, CS is expressed as a positive or absolute value, i.e., as described herein, CS = |CS|. Compressive stress (CS) may be greatest at the glass surface, and CS may vary as a function of distance d from the surface. Referring again to Figure 1, first compression layer 120 extends from first surface 110 to depth _d1 , while second compression layer 122 extends from second surface 112 to depth _d2 . Together these segments define the compression or CS of the glass ceramic 100. Compressive stress (including surface CS) is measured by a surface stress meter (FSM) using commercially available instruments such as FSM-6000 manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely on accurate measurements of the stress optical coefficient (SOC) related to the birefringence of the glass. The SOC is then measured according to Procedure C (Glass Disk Method) described in ASTM Standard C770-16, titled "Standard Test Method for Measurement of Glass Stress-Optical Coefficient," the contents of which are incorporated herein by reference in their entirety.

The compressive stress of the two compressive stress regions (120, 122 in Figure 1) is balanced by the tension stored in the central region of the glass (130). Maximum central tension (CT) and DOC values were measured using the Scattered Light Polarizer (SCALP) technique known in the art.

A compressive stress layer can be formed in the glass by exposing the glass to an ion exchange solution. In embodiments, the ion exchange solution may be molten nitrate. In some embodiments, the ion exchange solution may be molten KNO ₃ , molten NaNO ₃ , or a combination thereof. In some embodiments, the ion exchange solution may include less than or equal to about 100% molten _KNO3 , such as less than or equal to about 95% molten _KNO3 , less than or equal to about 90% molten _KNO3 , less than or equal to about 80% molten KNO3 % molten KNO ₃ , less than or equal to about 75% molten KNO ₃ , less than or equal to about 70% molten KNO ₃ , less than or equal to about 65% molten KNO ₃ , less than or equal to about 60% molten KNO ₃ , or smaller. In some embodiments, the ion exchange solution may include greater than or equal to about 10% molten _NaNO3 , such as greater than or equal to about 15% molten _NaNO3 , greater than or equal to about 20% molten _NaNO3 , greater than or equal to about 25% molten NaNO3 % molten NaNO ₃ , greater than or equal to about 30% molten NaNO ₃ , greater than or equal to about 35% molten NaNO ₃ , greater than or equal to about 40% molten NaNO ₃ , or greater. In other embodiments, the ion exchange solution may include about 80% molten KNO ₃ and about 20% molten NaNO ₃ , about 75% molten KNO ₃ and about 25% molten NaNO ₃ , about 70% molten KNO ₃ with about 30% molten NaNO ₃ , about 65% molten KNO ₃ with about 35% molten NaNO ₃ , or about 60% molten KNO ₃ with about 40% molten NaNO ₃ , and all ranges between the above values and subranges. In embodiments, other sodium and potassium salts may be used in the ion exchange solution, such as sodium or potassium nitrites, phosphates or sulfates. In embodiments, the ion exchange solution may include silicic acid, for example, less than or equal to about 1 wt% silicic acid.

The glass ceramic can be exposed to the ion exchange solution by immersing the glass ceramic in a bath of ion exchange solution, spraying the ion exchange solution onto the glass ceramic, or physically applying the ion exchange solution to the glass ceramic. According to embodiments, when exposed to the glass ceramic, the temperature of the ion exchange solution may be greater than or equal to 400°C to less than or equal to 500°C, such as greater than or equal to 410°C to less than or equal to 490°C, greater than or equal to 420°C to less than or equal to 480°C, greater than or equal to 430°C to less than or equal to 470°C, or greater than or equal to 440°C to less than or equal to 460°C, and all ranges and subranges between the above values. In embodiments, the glass ceramic is exposed to the ion exchange solution for a period of time greater than or equal to 4 hours to less than or equal to 48 hours, such as greater than or equal to 8 hours to less than or equal to 44 hours, greater than or equal to 12 hours to less than or equal to Equal to 40 hours, greater than or equal to 16 hours to less than or equal to 36 hours, greater than or equal to 20 hours to less than or equal to 32 hours, or greater than or equal to 24 hours to less than or equal to 28 hours, and all ranges and subdivisions in between Scope.

The ion exchange process may be performed in an ion exchange solution under processing conditions that provide an improved compressive stress profile such as that disclosed in U.S. Patent Application Publication No. 2016/0102011, the entire contents of which are incorporated by reference. Enter this article.

After the ion exchange process is carried out, it should be understood that the composition of the glass ceramic surface may be different from the composition of the glass ceramic as it is formed (ie, the glass ceramic before undergoing the ion exchange process). This is due to the replacement of one type of alkali metal ion (such as Li ⁺ or Na ⁺ ) in the newly formed glass by a larger alkali metal ion (such as Na ⁺ or K ⁺ ) respectively. In embodiments, however, the composition of the glass ceramic at or near the depth center of the glass article changes minimally during the ion exchange process and may be substantially the same or the same composition as the formed glass ceramic.

The glass ceramic articles disclosed herein may be incorporated into another article, such as an article with a display (or display article) (such as consumer electronics including cell phones, tablets, computers, navigation systems, etc.), construction articles, transportation articles (such as cars, trains, airplanes, maritime vehicles, etc.), electrical appliances, or any product that requires a certain degree of transparency, scratch resistance, abrasion resistance, or a combination thereof. Exemplary articles comprising any of the glass ceramic articles disclosed herein are shown in Figures 2A and 2B. Specifically, FIGS. 2A and 2B illustrate a consumer electronic device 200 including a housing 202 having a front surface 204, a rear surface 206, and sides 208; electronic components (not shown) located at least partially or entirely within the housing, It includes at least a controller, a memory, and a display 210 at or near the front surface of the housing; and a cover substrate 212 at or above the front surface of the housing so that it is above the display. In some embodiments, at least a portion of at least one of cover substrate 212 and/or housing 202 may include any of the glass articles disclosed herein. Example

The embodiments will be further illustrated by the following examples. It should be understood that these examples are not limited to the above-described embodiments.

Precursor glasses were prepared having the composition in Table 1 below. In Table 1, all components are in mol% and various properties of the glass compositions were measured according to the methods described herein. Table 1 Analysis(mol%) 1 2 3 4 5 6 SiO ₂ 50.0 54.0 54.1 54.2 54.2 48.3 Al ₂ O ₃ 21.0 20.8 20.9 21.0 21.3 23.6 ZnO 10.1 10.5 10.6 10.4 10.5 12.5 MgO 5.8 6.0 6.1 6.0 6.0 6.9 ZrO ₂ 3.4 2.3 1.9 2.2 2.2 2.3 TiO ₂ 4.1 2.2 2.2 1.7 1.2 2.2 Li ₂ O 3.9 Na ₂ O 0.1 2.6 2.6 2.9 3.1 2.6 BO 1.2 1.2 1.2 1.2 1.2 1.2 As ₂ O ₅ 0.1 0.1 0.1 0.1 0.1 0.1 NO ₂ 0.2 0.2 0.2 0.2 0.2 0.2 B ₂ O ₃ CaO Eu ₂ O ₃ Ta ₂ O ₅ La ₂ O ₃ P ₂ O ₅ Density (g/cm ³ ) 2.934 2.864 2.848 2.853 2.845 2.949 Hardness(GPa) 8.47 Poisson's Ratio 0.254 Shear modulus (GPa) 39.30 Young's modulus (GPa) 98.60 RI @ 589.3 nm 1.5847 Table 1 (continued) Analysis(mol%) 7 8 9 10 11 12 SiO ₂ 47.8 46.1 44.5 54.1 54.1 54.1 Al ₂ O ₃ 23.8 24.7 25.6 20.8 20.6 21.3 ZnO 12.7 13.2 13.7 10.5 10.4 10.3 MgO 7.1 7.4 7.7 6.0 6.0 5.8 ZrO ₂ 2.2 2.3 2.2 2.3 2.4 3.2 TiO ₂ 2.2 2.2 2.2 2.2 2.2 0.0 Li ₂ O Na ₂ O 2.7 2.7 2.7 2.6 2.6 3.7 BO 1.2 1.2 1.2 1.2 1.2 1.2 As ₂ O ₅ 0.1 0.1 0.1 0.1 0.1 0.1 NO ₂ 0.2 0.2 0.2 0.2 0.2 0.2 B ₂ O ₃ CaO Eu ₂ O ₃ Ta ₂ O ₅ La ₂ O ₃ P ₂ O ₅ Density (g/cm ³ ) 2.957 2.98 3.006 2.856 2.858 0 Hardness(GPa) 8.36 8.30 Pusumbi 0.257 0.252 Shear modulus (GPa) 39.0 39.0 Young's modulus (GPa) 97.9 97.6 RI @ 589.3 nm 1.5830 1.5840 Table 1 (continued) Analysis(mol%) 13 14 15 16 17 18 SiO ₂ 54.9 47.7 44.1 49.7 54.3 52.7 Al ₂ O ₃ 20.7 23.6 25.4 19.7 20.5 19.7 ZnO 10.4 12.5 13.6 9.6 10.1 MgO 6.0 7.0 7.7 5.4 15.9 5.6 ZrO ₂ 2.9 2.8 2.9 4.3 3.0 3.2 TiO ₂ 2.2 2.2 2.2 2.2 2.2 Li ₂ O Na ₂ O 2.7 2.7 2.6 3.6 2.6 2.5 BO 0.0 1.2 1.2 1.1 1.2 1.2 As ₂ O ₅ 0.1 0.1 0.1 0.1 0.1 0.1 NO ₂ 0.2 0.2 0.2 0.2 0.2 B ₂ O ₃ 3.9 CaO Eu ₂ O ₃ Ta ₂ O ₅ La ₂ O ₃ 2.5 P ₂ O ₅ 2.2 Density (g/cm ³ ) 2.829 2.967 3.016 2.726 0 Hardness(GPa) Pusumbi Shear modulus (GPa) Young's modulus (GPa) RI @ 589.3 nm 1.5832 1.6026 1.6117 1.5745 Table 1 (continued) Analysis(mol%) 19 20 twenty one twenty two twenty three twenty four SiO ₂ 51.4 53.1 51.7 54.1 52.9 56.7 Al ₂ O ₃ 19.1 18.9 20.1 20.9 21.6 22.4 ZnO 9.9 10.5 9.7 10.1 10.1 10.7 MgO 5.4 5.3 5.7 5.8 6.0 6.2 ZrO ₂ 3.3 3.3 4.8 TiO ₂ 2.1 2.2 Li ₂ O Na ₂ O 2.5 2.6 3.7 3.8 3.9 3.9 BO 1.1 1.2 1.1 As ₂ O ₅ 0.1 0.1 0.1 0.1 0.1 0.1 NO ₂ 0.2 0.2 0.2 B ₂ O ₃ CaO 0.3 Eu ₂ O ₃ 2.4 Ta ₂ O ₅ 5.2 La ₂ O ₃ 4.8 P ₂ O ₅ 2.6 5.2 Density (g/cm ³ ) 0 0 2.851 Hardness(GPa) 8.48 Pusumbi 0.252 Shear modulus (GPa) 37.6 Young's modulus (GPa) 94.0 RI @ 589.3 nm 1.5728

The density value refers to the value measured by the buoyancy method of ASTM C693-93 (2013). Hardness was measured using a nanoindenter as described above. Young's modulus and shear modulus are measured by the general ultrasonic resonance spectroscopy technique specified in ASTM E2001-13, named "Standard Guide for Resonant Ultrasound Spectroscopy for Defect Detection in Both Metallic and Non-metallic Parts". The refractive index (RI) of the precursor glass was measured at a wavelength of 589.3 nm. Table 2 ceramicization process condition B 1000℃ for 4 hours D 950℃ for 4 hours E 850℃ for 4 hours H 800℃ for 4 hours I 900℃ for 4 hours N Slow ramp 1 950°C for 4 hours O Slow ramp 1 850°C for 4 hours P 895℃ for 4 hours X 1050℃ for 4 hours

Table 2 provides the ceramicization process for forming glass ceramics from precursor glass compositions. Unless otherwise stated, the ceramization process involves heating the precursor glass in a furnace from room temperature to the specified processing conditions at a ramp rate of 5°C/min, holding for the specified time, and then cooling the furnace to ambient temperature. The ceramization process labeled Slow Ramp 1 Condition consists of heating the precursor glass from room temperature to 700°C in the furnace at a ramp rate of 5°C/min and then to the specified processing conditions at a ramp rate of 1°C/min.

The phase assembly of the glass ceramic formed by ceramizing the precursor glass composition was determined based on X-ray diffraction (XRD) analysis and is reported in Table 4 below. The content of residual glass, zinc spinel and tetragonal ZrO _phases in glass ceramics was measured using the Rietveld quantitative analysis method in wt%. The phases detected in the phase assembly decisions are described in Table 3 below. table 3 Mutually T Tetragonal ZrO ₂ G zinc spinel V lithium silicate B3 baddeleyite

Glass ceramics were produced from the ceramization process of Table 2 using the compositions of Table 1. The properties of the resulting glass ceramics and the ceramicization process used to produce the glass ceramics are reported in Table 4 below. In addition, some glass ceramics undergo ion exchange, as shown in Table 4. The density differences reported in Table 5 refer to the density change of the precursor glass when forming the glass ceramic. Table 4 glass composition 1 2 3 4 5 6 ceramicization process E B B B B B Density (g/cm ³ ) 3.061 2.975 2.957 2.963 2.950 3.091 Density difference(%) 4.15 3.73 3.69 3.71 3.56 4.59 Phase 1 G G G G G G Crystallite size phase 1 (Å) 68 148 200 263 523 169 Phase 2 T,V T T T T T Crystallite size phase 2 (Å) 115 137 190 233 166 Glass(wt%) 59 59 58 60 51 Zinc spinel (wt%) 38.1 39.3 39.3 37.0 46.4 Tet ZrO ₂ (wt%) 3.0 2.2 2.9 3.3 3.0 Hardness(GPa) 9.92 Pusumbi 0.208 Shear modulus (GPa) 44.1 Young's modulus (GPa) 106.6 RI @ 589.3 nm Table 4 (continued) glass composition 7 8 9 10 11 12 ceramicization process I I I D D B Density (g/cm ³ ) 2.978 2.981 Density difference(%) 4.10 4.13 Phase 1 G G G G G Crystallite size phase 1 (Å) 141 135 134 126 99 Phase 2 T T T T T Crystallite size phase 2 (Å) 131 130 77 117 88 Glass(wt%) 60 61 Zinc spinel (wt%) 27 37 Tet ZrO ₂ (wt%) 2.7 2.8 Hardness(GPa) Pusumbi Shear modulus (GPa) Young's modulus (GPa) RI @ 589.3 nm Table 4 (continued) glass composition 13 14 15 16 17 18 ceramicization process B B B O B Density (g/cm ³ ) 2.949 3.117 3.196 2.88 Density difference(%) 4.07 4.81 5.63 Phase 1 G G G G Crystallite size phase 1 (Å) 104 158 132 180 Phase 2 T T T T Crystallite size phase 2 (Å) 102 168 152 112 Glass(wt%) 60 50 44 64 68 Zinc spinel (wt%) 37 46 51 28 26 Tet ZrO ₂ (wt%) 3.4 4.0 4.3 8.2 6 Hardness(GPa) Pusumbi Shear modulus (GPa) Young's modulus (GPa) RI @ 589.3 nm Table 4 (continued) glass composition 19 20 twenty one ceramicization process B B N Density (g/cm ³ ) 2.931 Density difference(%) 2.73 Phase 1 G Crystallite size phase 1 (Å) 152 Phase 2 T Crystallite size phase 2 (Å) 139 Glass(wt%) 62 Zinc spinel (wt%) 30 Tet ZrO ₂ (wt%) 7.9 Hardness(GPa) 8.95 Pusumbi 0.21 Shear modulus (GPa) 39.9 Young's modulus (GPa) 96.4 RI @ 589.3 nm 1.5717 Table 4 (continued) glass composition 1 2 3 4 5 6 ceramicization process H I I I I I Density (g/cm ³ ) 3.056 Density difference(%) 3.99 Phase 1 G G G G G G Crystallite size phase 1 (Å) 55 130 145 183 220 151 Phase 2 V T T T T Crystallite size phase 2 (Å) 117 131 165 158 Glass(wt%) 61 63 61 94 52 Zinc spinel(wt%) 37.3 36.1 36.4 6.3 45.6 Tet ZrO ₂ (wt%) 2.2 1.1 2.2 n/a 2.2 Baddeleyite(wt%) MgTa ₂ O ₆ (wt%) Mullite(wt%) Cordierite(wt%) Table 4 (continued) glass composition 7 8 9 10 11 ceramicization process H H H P P Density (g/cm ³ ) 2.954 2.976 3.006 2.98 2.982 Density difference(%) -0.10 -0.13 0.00 4.16 4.16 Phase 1 no phases no phases no phases G G Crystallite size phase 1 (Å) 125 91 Phase 2 T T Crystallite size phase 2 (Å) 127 117 Glass(wt%) 51 48 46 59 61 Zinc spinel (wt%) 47 49 51 38 36 Tet ZrO ₂ (wt%) 2.3 2.6 2.8 2.6 2.6 Baddeleyite (wt%) MgTa ₂ O ₆ (wt%) Mullite(wt%) Cordierite(wt%) Table 4 (continued) glass composition 13 16 twenty one twenty two twenty three twenty four ceramicization process N N Q N N N Density (g/cm ³ ) 2.953 2.937 2.631 3.453 2.741 Density difference(%) 4.20 2.93 Phase 1 G G Crystallite size phase 1 (Å) 76 149 Phase 2 T T Crystallite size phase 2 (Å) * 98 Glass(wt%) 63 64 62 100 69 55 Zinc spinel(wt%) 33 28 30 17 11 Tet ZrO ₂ (wt%) 3.6 6.6 8.2 Baddeleyite(wt%) 1.2 MgTa ₂ O ₆ (wt%) 13.42 Mullite(wt%) 27.95 Cordierite(wt%) 6.03 Table 4 (continued) glass composition 2 10 11 2 10 11 ceramicization process I I I D D D Density (g/cm ³ ) 2.978 2.976 2.972 2.969 2.974 Density difference(%) 4.10 3.97 3.63 3.81 3.90 Phase 1 G G G G G G Crystallite size phase 1 (Å) 138 156 163 167 226 168 Phase 2 T T T T T T Crystallite size phase 2 (Å) 128 159 138 140 174 144 Glass(wt%) 61 60 60 60 60 60 Zinc spinel(wt%) 37 38 37 37 37 37 Tet ZrO ₂ (wt%) 2.58 2.52 3.13 3.3 3.1 3.7 Table 4 (continued) glass composition 2 2 10 11 10 11 ceramicization process N X X X N N Density (g/cm ³ ) 2.969 2.961 2.957 2.96 2.974 2.972 Density difference(%) 3.54 3.28 3.42 3.45 3.97 3.84 Phase 1 G G G G G G Crystallite size phase 1 (Å) 107 250 334 256 115 108 Phase 2 T T T T T T Crystallite size phase 2 (Å) 95 172 199 173 97 80 Glass(wt%) 61 60 60 60 61 60 Zinc spinel(wt%) 36 37 37 36 36 37 Tet ZrO ₂ (wt%) 3.2 3.4 3.5 3.9 3.2 3.5

Crystallite sizes are presented in Angstroms. Where the crystallite size is marked with "*", the crystallite size of the relevant phase has not been determined.

Figure 3 is a tunneling electron microscope (TEM) image of glass composition 5 after ceramicization at 1000°C for 4 hours. The darkest area in Figure 3 corresponds to the residual glass phase, the gray area corresponds to the zinc spinel-spinel solid solution crystal phase, and the brightest area corresponds to the titanium-containing _tetragonal ZrO crystal phase. As shown in Figure 3, the crystal phase forms a dendritic structure.

Figure 4 provides measured total transmittance in the visible wavelength range for a comparative clear glass sample, a comparative clear glass ceramic sample, and a glass ceramic formed by ceramized glass composition 2. Each sample is 1 mm thick.

5 is a photograph of a front view and a side view of a precursor glass that has been partially ceramicized by irradiation with a carbon dioxide laser, according to an embodiment. The transparent areas are residual glass, while the opaque areas contain the crystalline phase.

Unless otherwise stated, all constituent components, relationships and ratios described in this specification are provided in mol%. All ranges disclosed in this specification include any and all ranges and subranges encompassed by the broadly disclosed range, whether or not expressly stated before or after the disclosed range.

It will be apparent to those skilled in the art that various modifications and changes can be made in the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, this specification is intended to cover the modifications and variations of the various embodiments described herein provided they come within the scope of the appended claims and their equivalents.

100: glass ceramic 110: first surface 112: second surface 120: first compression layer 122: second compression layer 130: glass center area 200: consumer electronic device 202: housing 204: front surface 206: rear surface 208: Side 210: display 212: cover substrate d ₁ , d ₂ : depth

Figure 1 schematically depicts a cross-section of a glass ceramic having a compressive stress layer on the glass ceramic surface according to embodiments disclosed and described herein;

2A is a plan view of an exemplary electronic device incorporating any of the glass ceramic articles disclosed herein;

Figure 2B is a perspective view of the exemplary electronic device of Figure 2A;

Figure 3 is a tunneling electron microscope (TEM) image of a glass ceramic according to one embodiment;

4 is a graph of total transmittance as a function of wavelength for a comparative glass sample, a comparative glass ceramic sample, and a glass ceramic according to an embodiment;

5 is a photograph of a front view and a side view of a precursor glass that is partially ceramicized by irradiation with a carbon dioxide laser, according to an embodiment.

Domestic storage information (please note in order of storage institution, date and number) without Overseas storage information (please note in order of storage country, institution, date, and number) without

100: Glass ceramics

110: First surface

112: Second surface

120: First compression layer

122: Second compression layer

130: Glass center area

d ₁ , d ₂ : depth

Claims (10)

A glass-ceramic, comprising: a first crystalline phase including (Mg _x Zn _1-x )Al ₂ O ₄ , where x is less than 1; and a second crystalline phase including MgTa ₂ O ₆ ; wherein the glass-ceramic is opaque in the visible range, the glass-ceramic has a Young's modulus greater than or equal to 90 GPa, and the glass-ceramic has a hardness greater than or equal to 7.5 GPa, and wherein the glass-ceramic further comprises: 35 mol% to 55 mol % SiO ₂ ; greater than or equal to 18 mol % Al ₂ O ₃ ; greater than or equal to 5 mol % MgO; and greater than or equal to 2 mol % P ₂ O ₅ . The glass-ceramic as claimed in claim 1, wherein x is greater than 0. The glass-ceramic as claimed in claim 1 or claim 2, wherein: the glass-ceramic further includes at least one of Li ₂ O and Na ₂ O; and/or the glass-ceramic further includes: 0 mol% to 14 mol%. ZnO; 0mol% to 5mol% TiO ₂ ; 0mol% to 5mol% Na ₂ O ; 0mol% to 5mol% Li ₂ O ; 0mol% to 2mol% BaO; 0mol% to 4mol% B ₂ O ₃ ; 0mol% to 1mol% CaO; 0mol% to 3mol% Eu ₂ O ₃ ; 0mol% to 6mol% Ta ₂ O ₅ ; 0mol% to 5mol% La ₂ O ₃ ; 0mol% to 0.1mol% As ₂ O ₅ ; and 0 mol% to 0.3 mol% SnO ₂ ; and/or ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃

6mol%; and/or the glass ceramic substantially does not contain TiO ₂ ; and/or ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃

5.5 mol%, and the glass ceramic includes at least one of the following: La ₂ O ₃ ; Ta ₂ O ₅ ; and greater than or equal to 2 mol% Li ₂ O; and/or ZrO ₂ +TiO ₂ +Eu ₂ O ₃ +Ta ₂ O ₅ +La ₂ O ₃

5.1 mol%, and the glass ceramic includes less than 2 mol% Li ₂ O and essentially does not contain La ₂ O ₃ and Ta ₂ O ₅ . The glass-ceramic as claimed in claim 1 or claim 2, wherein: the glass-ceramic exhibits a crystallinity of at least 35wt%; and/or the glass-ceramic has a Young's modulus greater than or equal to 100 GPa to less than or equal to 125GPa; and/or The glass-ceramic has a hardness greater than or equal to 8 GPa and less than or equal to 13 GPa; and/or the glass-ceramic is substantially colorless; and/or the glass-ceramic includes a compressive stress region extending from a surface of the glass-ceramic to a compression depth. The glass-ceramic according to claim 1 or claim 2, wherein the second crystal phase further includes tetragonal ZrO ₂ . The glass-ceramic of claim 1 or claim 2, wherein the glass-ceramic substantially does not contain ZrO ₂ and the second crystal phase further includes at least one of mullite and cordierite. The glass-ceramic of claim 1 or claim 2, wherein the glass-ceramic substantially contains no nucleating agent and the second crystal phase further includes mullite and cordierite. A consumer electronic product includes: a casing, including a front surface, a rear surface and several sides; several electronic components, at least partially located in the casing, the electronic components include at least one controller, a memory The body and a display are at or near the front surface of the housing; and a cover substrate is disposed on the display, wherein at least a part of the housing includes the glass ceramic described in claim 1 or claim 2 . A method of forming a glass ceramic, comprising the steps of: ceramizing a precursor glass to form a glass ceramic that is opaque in the visible range, wherein the glass ceramic includes: a first crystalline phase, including (Mg _x Zn _1-x )Al ₂ O ₄ , wherein x is less than 1; and a second crystalline phase including MgTa ₂ O ₆ ; wherein the glass-ceramic has a Young's modulus greater than or equal to 90 GPa and the glass-ceramic A hardness greater than or equal to 7.5 GPa, and wherein the glass-ceramic further includes: 35 mol% to 55 mol% SiO ₂ ; greater than or equal to 18 mol% Al ₂ O ₃ ; greater than or equal to 5 mol% MgO; and greater than or equal to 2 mol % of P ₂ O ₅ . The method of claim 9, wherein the glass-ceramic further includes: 0 mol% to 14 mol% ZnO; 0 mol% to 5 mol% TiO ₂ ; 0 mol% to 5 mol% Na ₂ O; 0 mol% to 5 mol% Li ₂ O; 0 mol% to 2 mol% BaO; 0 mol% to 4 mol% B ₂ O ₃ ; 0 mol% to 1 mol% CaO; 0 mol% to 3 mol% Eu ₂ O ₃ ; 0 mol% to 6 mol% Ta ₂ O ₅ ; 0 mol% to 5 mol% La ₂ O ₃ ; 0 mol% to 0.1 mol% As ₂ O ₅ ; and 0 mol% to 0.3 mol% SnO ₂ .